Cross-platform app development cost for legal & professional services

There is no single figure, and quoting one would be the least useful thing this page could do — the same pairing spans several-fold depending on scope, compliance and how many surfaces you ship. What this page gives you instead is what the pairing demands: the regimes that may apply, the systems of record you will be asked to integrate with, the device matrix and the release path. The calculator below is already fixed to Cross-platform and legal & professional services — answer what is left and it returns a cost range, hours, timeline, team and running costs for your scope.

Because legal & professional services brings its own obligations before you write a feature: SOC 2 Type II, Professional confidentiality rules, GDPR may apply, you will be asked to integrate with systems like DocuSign / Dropbox Sign and iManage / NetDocuments / SharePoint, and there are typically 5 distinct roles rather than one. The platform contributes its own separate costs — the device matrix, App Store & Google Play review — and those are independent of the industry.

In this model a single native app is the baseline. Two native apps cost about 1.7× that, because the second platform reuses the product thinking, API and design but repeats the implementation and its own test matrix. One cross-platform codebase costs about 1.24× the baseline plus fixed bridge hours. So against two native builds you save roughly 25–30% of client engineering — a real saving, but smaller than the "half price, one codebase" pitch suggests, because testing does not halve.

Flutter renders its own widgets, so the UI is highly consistent across platforms and animation-heavy interfaces behave predictably; the cost is that nothing looks natively platform-idiomatic unless you make it. React Native uses native components and shares language and often code with a web front end, which matters a great deal if you already have a React team. For a greenfield mobile-only product, Flutter is usually the more predictable build. For a team already writing TypeScript, React Native is usually the cheaper hire.

Yes, and clients increasingly expect it, but the professional liability changes the engineering. Every AI output needs source attribution, a human review step and an audit record of who accepted what. Retrieval over the firm’s own documents rather than open-ended generation is the pattern that works. Budget $50,000–$120,000 for a properly grounded, evaluated implementation — most of that in retrieval quality and evaluation rather than the model call.

It is a planning estimate, not a quote. The band shown is roughly plus or minus 15–20% for a well-defined scope, and wider while requirements are still moving. It is built from engineering hours per discipline, converted at our blended delivery rate, so the hours are directly comparable to a real proposal line by line — but a firm price needs a technical specification, which is the step after budgeting.